Damping device



Aug. 2,1927, 1,637,361

W. E. TRUMPLER DAMPING DEVICE Filed Aug. 25, 1925 CII Patented Aug. 2, 1927.

UNITED STATES PATENT oFFlcE.

WILLIAM E. TRUMPLER, OF WILKINSBURG, PNNSYLVANIA, ASSIGNOR TO'WESTING- `HQUSE ELECTRIC & MANUFACTURING COMPANY, A CORPORATION OFPENN'SYL- VANIL DAMPING DEVICE.

p Applicationlled August 25, 1925. Serial No. 52,370.

My invention relates to balancing machines, and more particularly to apparatus for dynamical] balancing rotors, such as armatures for ynamo-electric machines.

It is among the objects of my invention to rovide a balancing machine embodying a` amping device of simple, compact and durable construction for damping the vibrations of the oscillatable bed member.

Another object 0f my invention is to provide electromagnets for damping the vibration of balancing machines which shall be designed to dampen the vibration of the movable bed member withoutinfluencing its frequency of vibration to any material exbent. i

nIn my co ending application, Serial No.

736,458, tile SeptfS', 1924, II have described a balancing machine comprisinga station ary base, a movable fulcrum support, an oscillatable bed member-carried by said sup port, and means for jour-nailing a rotor to be tested on the bed member; balancing machine distinguishes from prior types in that the movable or yieldingelements are arranged vertically relative to the fulcrum axis as distinguished from vthe horizontal arrangement heretofore employed.

In that application, I have further disclosed electromagnetic damping means associated with the movable bed and fulcrum support-'for damping the vibrations thereof.

My present invention relates to an im-4 proved type of electromagnet, for the vertical type of balancing machines, which is designed and constructed to effectively dampen the vibrations of the balancing ma-` chine bed without influencing the frequency of vibration, and I have foundthat the electromagnet described in my prior application was deficient in that it had an undesirable influence on the frequency of the vibrating system, thereby requiring adjustment of the speed of rotation ot the member being tested for any change in thc excitation of the magnets. This deficiency was due to the increase of magnetic force with a decrease of air gap, which introduced a negative spring factorjthat reduced the natural frequency ot vibration.

This type ot I overcome .these difficulties by utilizing dampening magnets having corrugated pole surfaces in which the corrugations run either' straight (parallel to each other) or concentric. curved or circular, but is preferably of a gear-tooth shape. This form ot pole surface provides a constant pull for variable air. gaps, and variable excitation of the magnets does not cause a departure from this characteristic, thus, not materially influencing the frequency of vibration of the vibrating system. The electro-magnets themselves` are secured to the `balancing machine in the same manner as illustrated and described in the above-mentioned application,` and their general function and characteristicsl are likewise the same as therein described, with the except-ion of the improvements which will be hereinafter set forth. c

In accompanying drawing constituting a part hereof and in which like reference characters designate like parts,

f Figure `1 is a view, partially in section and partially in end elevation of a balancing machine embodying the principles of my invention.

Fig. 2 is a view in side elevation thereof, and

Fig. 3 is an enlarged detail view ofthe improved type of electromagnet that is utilized in the machine shown in Fig. 1.

Referring to Figs. 1 and 2, the device there? in illustrated comprises a lower stationary base `or bed member 1 carrying a movable fulcrum support 2 that engages an oscillatf ablebed member 3. l n

AThe fulcrum support 2 is `mounted on the ways 4 oi the base l and may be secured in anyixed position by a plura-lityof T-bolts 5. The oscillatable bed member 3 isheld in position by a plurality of upper and lower vertical fulcrum members G of a resilient type, and one end of the bed is yieldingly restrained against movement, by a spring member. T. The bed member 3 is provided with yokcs 8, whichare secured thereon by' thumb screws 9 to permit adjustment of their horizontal center distance; and 'these yokes are provided with vertical slotted The profile may be straight,

' zontally along the ways 4 of the bed-mein. berl by a hand wheel 15, and the spring The flcrummember is movable boris" element 7 on the hed 31 may bei stenedor flexedfby 'horizontally adjusting its pedestal member or"spring"spport 16 to vary uthe` leverage on the spring elementi:

tenedby screwbolts 19 to a pair of plates 2O that arefixe'd tothebed member 3. These magnets'are provided with cores21 having extended poleends 22, the faces of which are rovided withv` yteeth or corrugations 23.

imilarpole members24 are secured to thev In the operation of the balancing machine,

'the rotation 'of-*the armature 12, which iS eifectedbyits connection through the belt 13,"will induce a vibration in the oscillatable bed lmember corresponding to the fdegree of dynamicunbalaneefor the amount of unbalanced massv in therotor. The oscillatory movement ofthe bed 'member about the vertical resilient fulcrums 6' tbu'sfindicates an unbalancedcondition of the rotor and the approximate amount of the correctionnecessary to lbalance the same, which has been more fully set forth in the afore-mentioned application. I l

rIt is very necessary, however, to introducea dampening mediumfor restraining the'vibration of the'bed member and for this purpose the magnet coils 18 arekr energized to' setup a magnetic force between the faces of their poles. I have found that, by utiliz ing thetype of' corrugated faces -shown in VFigf,'effective damping may be introduced without influencingV the frequency of vibra- Y tion'of the' system or without such vibration being affected in rdegree by the `speed of rotation "of therotor.` i l"Although 1 have shown a'particular applicatioii of 'electromagnets having irregularly shaped pole faces, Ait is obvious that suchmagnets may be utilized for other purposes vwhere it is desired to obtain variable .air 'gaps for changing' excitation, and furthermore,` the irregularities of the pole faces maybe of any suitable shape ordesign without departing'y from"the principles herein set forth. Although I'haveillustrated the magnets as applied to the vertical type of balancing machine, they may obviously be applied to a machine of the horizontal type.

I claim as my invention:

1. A balancing machine comprising a stationary base and a vibratory bed, and electromagnetic damping means for said bed, said means comprising electromagnets having toothed pole pieces secured to said base i and bed and ada ted to dampen ltlie vibratory movement o said bed withoutmaterial- 4ly influencing the frequency oit-vibration f thereof; v., 2,-;:gball9nf A machine comprising a stationary base and a vibratory bed, and electromagnetic ,damping means-,forsald bed,

ing tooth kshaped pole faces secured to Said ment. i

3. A balancingmachine.comprising a sta# tionary base and a vibratory bed, and electromagnetic damping means forsaidbed, said means comprising electromagnets hav? ing corrugated pole fiices Idisposed towards a said means comprising electromagnets hav- Aj plurality ofielectromagnets 18 are fas-fI eachother in cooperative working alinement..

f 4. A balancing machine comprisinga stationary base and a vibratory bed, andelectromagnetic damping means forl said bed,

said meanscomprising electromagnets having corrugated pole faces disposed towardsl` each other in spaced relationand in. cooper`- ativeworking alinement to provide anlair-i gap therebetween.` f

5. A balancing machinel comprisingk a staf tionary base and a vibrator-y bed,and elec# tromagnetic damping means for; said bed, said means comprising electromagnets haying irregularly shaped pole faces securedig)` said baseand bed incooperative working alinement, said irregularly shaped pole faces being adapted to provide a variable air. gap^ to correspond tov variations of applied mag;`

netic force.

6. A.balancingfmachine comprising a stay,

tionarybase and a vibratory bed, and electromagnetic damping means for said bed, said means comprising electromagnetshaving corrugated polefacesdisposed towards each other in spaced relation, with the projections of the corrugated surface of one face in alinement with the spaces of the cooperating member. j i .i l

7. A balancing machine comprising a base, a fulcrum support movablymounted thereon, a springsupportsecured ,to said base, a plurality ofllexible membersfsecured to said supports, an oscillatable bed carried by said` fulcrum support, means for moving the latter relative tosaid bed,'means for yieldingly restraining movement of'said bed, and means for journalling a rotor to be tested on saidbed. saidrestraining means comprising a plurality of electromagnets associated with said fulcrum su portand bed i and having corrugated pole aces.

los

llU

8. A balancing machine comprising 2L nets secured to said fulcruin support and bed base, a fulcruin support movably mounted having irregularly shaped pole faces in C0- there'on, a spring support secured to said operative alnement. base, a plurality of flcxible members secured In testimony whereof, I have hereunto to said supports, and oscillatable bed carried subscribed my naine this 6th Clay of August by said fulcrum support, means for moving 1925. the lat-ter relative to said bed, electromag- W'ILLIAM E. TRUMPLER. 

